Art of pickling metals



Patented @et. 311., 1922.

STATES OFF! ART OF PICKLING METALS.

No Drawing.

To all whom it may concern:

Be it known that I, O'r'ro Voenn, engineer, a citizen of Prussia, residing at 52 Wildenbruchstreet, Dusseldorf-Oberkassel, Prussia, Germany, have invented a new and useful Im rovement in the Art of Pickling Metals; and I do hereby declare the following to be a full, clear, and exact description of the same.

The present invention refers to an improvement in the art of pickling iron. especially malleable iron, steel, iron alloys and articles therefrom as wires, wire ropes, sheets, etc., with acids as diluted mineral acids, for instance diluted sulphuric acid, or hydrochloric acid before the further working as galvanizing, coating with fluid metals, etc. The object of the lmprovement is to avoid the brittleness of the iron being often a consequence of the pickling of iron with acids or acid substances carried out for'destroying the superficial layer of oxides produced by the rolling process and such like.

The new composition for pickling iron, steel, iron alloys or articles therefrom consists of mineral acids or acid substances used in the pickling of iron or iron alloys and organic substances having the property of avoiding 'the evolution of hydrogen in the action of acids or acid substances on iron as crude anthracene, the waste products of the naphthalene production, the waste lyes from the sulphite cellulose manufacture. Especially suitable for the purpose of my invention are anthracene residues. A suitable composition is hydrochloric acid of 22 B6. and 1-2 per cent of anthracene residues or sulphuric acid of 1012 B. and 1-2 per cent of anthracene residues, or sodium bisulphate solution and 1-2 per cent of anthracene residues. The composition can also be used as coating for iron, steel, iron alloys or articles therefrom for preventing rust or removing rust.

The process for pickling iron, etc., consists in dipping the articles into the composition at ordlnary temperature or with a gentle heating. One may allow the articles to lie for a long time in the liquid without any brittleness or destroying being effected. Only the superficial layer will be removed without the metallic iron being efiected. In consequence less substance is dissolved and less acid is used than in the hitherto known processes. The wire preserves its circular shape and it may be drawn with less power.

Application filed August 13, 1919. Serial No. 317,341.

The pickled material is less subjected to the attack of rust. The sheetswill obtain a smoother surface, the consequence of which is that a smaller quantity of tin or zinc is required in the tinning or zincing processes.

A modification of the resent invention consists in that the composition besides acids or acid substances contains the extracts of the substances produced by the destructive distillation of carbonaceous matter, extracted by treating the said substances by means of inorganic acids, neutral or acid salts, organic solvents as hydrocarbons, for instance petroleum, tar oils, the said extracts having been separated from the undissolved constituents of the products of the destructive distillation of carbonaceous matter. Whereas the above described invention employs the immediate saidproducts of the destructive distillation of carbonaceous matter without further treatment the modification employs only the extracted substances. A. suitable composition consists of diluted mineral acids (sulphuric acid, hydrochloric acid) or acid substances (as sodium bisulphate) and 110% of the extracts obtained by treating anthracene residues, sulphite cellulose waste lyes, or the residues of the naphthalene distillation with 3-4 parts by weight of sulphuric acid, and separating the obtained solution from the undissolved.

Another suitable composition contains besides the mineral acids or acid substances the waste acids, separated from the treatment of hydrocarbons (as for instance petroleum, brown coal tar oils, coal tar oils, paraifins, etc.) with sulphuric acid, especially concentrated. Also the so called acid resins obtained by the said purification of the hydrocarbons with concentrated acids may be added to the mineral acids or acid substances.

The said extracts may be added alone to the mineral acids or acid substances or in mixture with the unextracted residues of the destructive distillation of carbonaceous matter.

The extracts have the advantage that the residues of the extraction may be employed as pitch, etc., for other technical purposes and that the undissoluble substances do not contaminate the mineral acids, whereas es ethe superficial layer of oxides from iron, iron alloys and steel or for preventing rusting comprising the residues of the destructive distillation of carbonaceous matter and acid substances capable of dissolving iron oxides.

2. A composition of matter for dissolving the superficial layer of oxides from iron, iron alloys and steel or for preventing rusting comprising the residues remaining in the distillation of anthracene from tar and acid substances capable of dissolving iron oxides.

3. A composition of matter for dissolving the superficial layer of oxides from iron, iron alloys and steel or for preventing rusting comprising extracts of the residues of the destructive distillation of carbonaceous matter and acid substances capable of dissolving iron oxides. v

4. A composition of matter for dissolving the superficial layer of oxides from iron, iron alloys and steel or for preventing rusting comprising the waste acids from the purification of hydrocarbons With sulphuric acid and acid substances capable of dissolving iron oxides.

5. The process of pickling iron, iron alloys and steel which comprises dipping the metal to be' pickled into a mixture of the residues of the destructive distillation of carbonaceous matter and acid substances capable of dissolving iron oxides.

'6. The process of pickling iron, iron alloys and steel which comprises dipping the metal to be pickled into a mixture of the residues remaining in the distillation of anthracene from tar and acid substances capable of dissolving iron oxides.

7. The process of pickling iron, iron alloys and steel which comprises dipping the metal to be pickled into a mixture of extracts of the residues of the destructive distillation of carbonaceous matter and acid substances capable of dissolving iron oxides.

8. The process of pickling iron, iron alloys and steel which comprises dipping the metal to be pickled into a mixture of the Waste acids from the purification of hydrocarbons with sulphuric acid and acid substances capable of dissolving iron oxides.

In testimony whereof, I have signed my name to this specification.

. OTTO VOGEL. 

